| 摘要 |
<p>The object of the invention is a transceiver for transmitting and receiving an RF signal on at least two operating frequency ranges. One idea of the invention is to use a transceiver based on the direct transform and where the mixing frequency is generated with the aid of the same synthesiser. This is preferably realised so that when operating on frequency ranges far from each other the output signal of the synthesiser is divided with different divisors in order to generate the mixing frequency (211, 231, 261, 281). When operating on frequency ranges which are close to each other the divisor (P) used in the feedback of the synthesiser is advantageously changed (248). With the aid of the invention two mixing signals with a mutual phase difference of 90 degrees can be generated in connection with the division of the synthesiser frequency, whereby no RC phase shifters are required in the signal line, and a good phase accuracy is obtained which is independent of the frequency. <IMAGE></p> |
